If you want to make money with an airplane, you have to keep the airplane in the air. Every time an airplane is grounded it is extremely costly for the owner or airline.
AOG (Air is a term used in the Aerospace industry when a mechanical problem in an aircraft makes the plane unsafe for flying. According to a recent study, smaller airlines dealing with AOG situations can lose north of $20,000 a day, while larger airlines in Western countries with AOG’s often can cost up to $150,000 an hour.
The current cost for a new Boeing 777 fluctuates from $261.5 Million to $320.2 Million depending on the model that you choose. The average dry lease (only plane without crew) cost for the Boeing 787-9 ranges between $1.1 Million and $1.25 Million a month or over $36,000 a day. This does not take into account the cost of maintenance/parts or the revenue airlines are missing out on from customers.
As you can see, the Aerospace industry is a high stakes game and getting whatever part that is keeping the plane on the ground to the air plane as fast as possible is of the highest importance.